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I was actually hoping that, with the release of documentation on AMD's graphics cards, we'd see demos coded "on the metal", without passing through the standard

I was actually hoping that, with the release of documentation on AMD's graphics cards, we'd see demos coded "on the metal", without passing through the standard graphics stack. That won't be possible on windows, since you can't just boot to console and then bang the pci bus yourself, but would be possible on linux. It could even be written as a kernel module for maximum effect.

seanmcdirmid 13y ago
DirectX is pretty efficient already. I don't think you would be able to push many more polygons going to the metal.
- bni 13y ago
  The impressive graphics (for the hardware) on current gen consoles showns what is possible when going to the metal, bypassing several layers of WDM, scheduler, drivers and DirectX.
  - CJefferson 13y ago
    I believe, on the Xbox 360 at least, you have to go through the scheduler, drivers and DirectX. There is no direct hardware access.
    - Narishma 13y ago
      DirectX on the Xbox 360 is very lightweight and exposes a lot more of the hardware than what you get on Windows.
  - seanmcdirmid 13y ago
    No it doesn't. It takes a lot of effort with Cell just to reach parity, Xbox is basically DX9. You program the GPU by writing shaders that run right on the GPU, the only perf increases to be had involve how fast you can move data on and off the GPU. Eliminating all abstraction might give you a few percentage points, not enough to do anything that we would consider amazing under current circumstances.
wladimir 13y ago
That would be nice, but I think the issue is less one of documentation (lots of demosceners into reverse engineering) but that there are (a) just too many different graphics cards out there (b) the platform lifetime is very short (c) less motivation for hw specific tricks as "everything is already possible"; GPUs these days are parallel general purpose computing hardware, at most you'll speed up something a bit. If you make your demo to work on one ATI card you will have a small audience at most, and the card will be out of the market in a year and all the tricks you learnt were for nothing. And if you want it to work on more hardware you get into the device driver business, and that rules out special tricks for specific hardware to do non-standard rendering anyway... Back in the days of home computers there was one longer-lived hardware platform that many people were using. There is a faint hope that initiatives such as the Raspberry Pi may bring people to "standardize" on one more or less ubiquitous platform for longer time, but I'm afraid this ship has sailed. So it makes sense for demosceners to focus on what is possible on the higher, portable API level.

seanmcdirmid 13y ago

DirectX is pretty efficient already. I don't think you would be able to push many more polygons going to the metal.

bni 13y ago
The impressive graphics (for the hardware) on current gen consoles showns what is possible when going to the metal, bypassing several layers of WDM, scheduler, drivers and DirectX.
- CJefferson 13y ago
  I believe, on the Xbox 360 at least, you have to go through the scheduler, drivers and DirectX. There is no direct hardware access.
  - Narishma 13y ago
    DirectX on the Xbox 360 is very lightweight and exposes a lot more of the hardware than what you get on Windows.
- seanmcdirmid 13y ago
  No it doesn't. It takes a lot of effort with Cell just to reach parity, Xbox is basically DX9. You program the GPU by writing shaders that run right on the GPU, the only perf increases to be had involve how fast you can move data on and off the GPU. Eliminating all abstraction might give you a few percentage points, not enough to do anything that we would consider amazing under current circumstances.

wladimir 13y ago

That would be nice, but I think the issue is less one of documentation (lots of demosceners into reverse engineering) but that there are (a) just too many different graphics cards out there (b) the platform lifetime is very short (c) less motivation for hw specific tricks as "everything is already possible"; GPUs these days are parallel general purpose computing hardware, at most you'll speed up something a bit. If you make your demo to work on one ATI card you will have a small audience at most, and the card will be out of the market in a year and all the tricks you learnt were for nothing. And if you want it to work on more hardware you get into the device driver business, and that rules out special tricks for specific hardware to do non-standard rendering anyway... Back in the days of home computers there was one longer-lived hardware platform that many people were using. There is a faint hope that initiatives such as the Raspberry Pi may bring people to "standardize" on one more or less ubiquitous platform for longer time, but I'm afraid this ship has sailed. So it makes sense for demosceners to focus on what is possible on the higher, portable API level.